Cranking raw water cooled the engine too much then vapor or smoke

[redtim]

Tim,
There is a "T" fitting on the hose between the water pump and the thermostat. The "T" fitting is where the cooling water enters the block and the volume is controlled by the thermostat. If you have a by-pass valve it would be located between the "T" connection and the thermostat. They are an aftermarket product and are available from our host. Some of the guys here who have lost faith in their thermostats or like to have a manual means of controlling the temperature have installed them and from all accounts like them.

Just a way out thought, but if your located where the outside temperature is cold you could be exhausting some condensation as part of what we can see.

Chuck

I'm in the San francisco bay, so not too cold around here. Thanks for the info on the bypass. I'm thinking about disconnecting the water line from the exhaust and letting it run for a while to see if the vapor is still visible.

Is there any reason the hot water needs to run through the exhaust outlet if running for a while?

[JOHN COOKSON]

redtim
I think you have the idea.
Here was my experience with my late model RWC engine:
I led a hose from the manifold to the cockpit and started the engine. My feet were in water so I thought I'd aim the hose over the side of the boat. I did this and revved the engine up and shot a stream of water across the finger pier and into my neighbors boat's cockpit!
To say I was amazed would be an understatement.
If you are getting this sort of output after the water goes through the engine then there is a blockage to flow after the engine somewhere. As you have figured out this is why I wanted you to disconnect the hose after the manifold and check the flow.

You can run the engine with no water coming out the exhaust for awhile. Be careful not to heat damage any hoses or plastic mufflers.

TRUE GRIT

[edwardc]

Is there any reason the hot water needs to run through the exhaust outlet if running for a while?

YES!! Without the cooling water, the high temperature exhaust will quickly damage the rubber exhaust hose. The damage will be on the inside and not readily apparent. The hose will begin to delaminate and buckle internally, causing an exhaust blockage.

EDIT: John types quicker than me!

[redtim]

Thanks all,
will do some more checking this weekend.

One thing to note, Looking at the exhaust hot section,
I have something similar to this

http://www.moyermarine.com/cgi-bin/shopper.cgi?search=action&category=EXHT&keywords=all&template=Templates/B000_storebuilder.html

but the whole thing is a bit smaller and the water barb is higher up on the hot section.

I also noticed that the description there indicates I should have a continuous downhill flow, the rubber hose heading to the exhaust port is a sagging tube, could that be causing problems? I haven't been able to inspect the full length of the tube, but it seems like this setup would have no further restrictions down the line save for a kinked hose?

redtim
I think you have the idea.
Here was my experience with my late model RWC engine:
I led a hose from the manifold to the cockpit and started the engine. My feet were in water so I thought I'd aim the hose over the side of the boat. I did this and revved the engine up and shot a stream of water across the finger pier and into my neighbors boat's cockpit!
To say I was amazed would be an understatement.
If you are getting this sort of output after the water goes through the engine then there is a blockage to flow after the engine somewhere. As you have figured out this is why I wanted you to disconnect the hose after the manifold and check the flow.

You can run the engine with no water coming out the exhaust for awhile. Be careful not to heat damage any hoses or plastic mufflers.

TRUE GRIT

[67c&ccorv]

Let's start from the beginning - what motor do you have?

An early model or a late model A4?

Because it makes a difference in water flow out the transom with an early model Dole thermostat system.

[redtim]

Let's start from the beginning - what motor do you have?

An early model or a late model A4?

Because it makes a difference in water flow out the transom with an early model Dole thermostat system.

It's an atomic 4

It has an oil fill tube over the flywheel, which seems to indicate late model?

Also, after getting the tach working, I noticed that the engine tops out at 1500 - 1700 rpms. below that, I don't notice much vapor exiting the transom, after that it's billowing out.

[67c&ccorv]

It's an atomic 4

It has an oil fill tube over the flywheel, which seems to indicate late model?

Also, after getting the tach working, I noticed that the engine tops out at 1500 - 1700 rpms. below that, I don't notice much vapor exiting the transom, after that it's billowing out.

Not necessarily - do you have a serial number or year of manufacture?

What type of thermostat do you have?

[redtim]

The boat is a 74 Ericson 27, the engine... I'm not so sure.

I would guess it was installed aftermarket due to all the weird holes cut around it for access, but who knows.

I'll look for the date stamp when I get back on the boat this week.

[BunnyPlanet169]

It's an atomic 4

It has an oil fill tube over the flywheel, which seems to indicate late model?

Also, after getting the tach working, I noticed that the engine tops out at 1500 - 1700 rpms. below that, I don't notice much vapor exiting the transom, after that it's billowing out.

Take a couple pictures of your engine when you're out there - that'll help identify it.

Billowing white vapor is usually not a good thing, sorry. But let's burn that bridge when we come to it.

[BadaBing]

Redtim
Take a few pictures. They will help the MBPs better understand what your trying to describe.
What you are showing as a water lift muffler.some of them are made of plastic or fiberglass and WILL melt if run even for a short time with no water.

I suggest this, because it worked for me, disconnect the discharge hose from the manifold, WHEN THE ENGINE IS COLD, and add in a pc of hose going to a f gal bucket. At idle you should be pumping at about 4from through the engine.
If your going to rev the engine you will fill your bilge or your neighbors boat in short order. Do this test with a cold.engine and don't run it very long or you risk trashing parts down strewn in the exhaust gas as described above.

Because your raw water cooled(?) The block or head may be full.of crud. Have you done an acid flush on the engine? Actually 170 at FOT under load isn't bad at all and my Tartan blows some steem or it did when I pushed her.

If you have good flow through the ,and.I'm.guessing you do, you might want.to look at that water lift muffler. Someone posted a picture e here a while.back of one packed full of crud.
1500- 1700 at FOT is a tad low. You would.expect.to see 24, 25, 2700 if your prop.is correct and the engine is healthy. 1500 is low cruising rpm.

A little steam at high end under load isn't a big deal. Aft e r all your mixing water with some VERY hot exhaust gasses. But your lower rpm suggest something is going on.
Ok pictures pictures pictures. Did I suggest you share some pictures? ( of the engine, exhaust gas, hose configurations. Pictures of the kids are nice but won't be much help.
Bill

[redtim]

Ok, here's a couple pictures.

The Engine is stamped with a date from 1974, same year as the boat, and the serial number starts with 295. Does that mean it's a fully late model?

I haven't had the exhaust system apart yet, I've been spending more time sailing than working. Sorry to rub it in for everyone that's not in the warmer parts of the country right now!

A question about symptoms of blocked exhaust.

reading this tidbit

http://www.moyermarine.com/exhaust.htm

makes me think that if a blockage was to blame for my low RPMs it would happen when I was at idle as well. Any thoughts on whether or not that assumption rings true?

Could it be that I just have an incorrectly sized prop???? Looking back over the POs service records, I found a note from a hull cleaner that there was no prop. HMMMM??? wonder what the new prop looks like?

Gonna have to take a swim i guess. That's what I get for gloating about sailing all the time, the air may be warm, but the bay is COLD!

[redtim]

Not necessarily - do you have a serial number or year of manufacture?

What type of thermostat do you have?

In the post above I've posted a picture of the thermostat housing, not sure what's under there.

And the serial number starts with 295, year of manufacture is 1974

[hanleyclifford]

Notice that street 90 bringing exhaust out of that manifold.

[redtim]

Notice that street 90 bringing exhaust out of that manifold.

Seems pretty similar to the MM catalina style exhaust. Is that one considered sub par?

[hanleyclifford]

Street is good

Seems pretty similar to the MM catalina style exhaust. Is that one considered sub par?

Not at all. I like street in this application for strength, simplicity and dimension.